[Q]problem transferring files to external sd

http://forum.xda-developers.com –
so, I've encountered problems transferring files to the removable sd card, when i try to copy something it indeterminately sits on "discovering" and in the mean time it crashes explorer ( not internet explorer) and also the phone completely freezes and has to be restarted. same happens when i try deleting stuff out of the sd card from windows and mac as well.
the same does not happens to the internal memory. And so far this is what i have done to see if it fixes the problem:
tried a couple different sd cards- did not work (was able to get rid of some files, but then it just wen
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